Don't get it, mate.
I would say it was a good tutorial, but when i think about it, it only is a good tutorial if it explains it clearly and thoroughly to the audience. I understood but not fully so it helped a bit but not really. If your target audience is people who do not know how to make preloaders which is kinda obvious, I don't think you succeded. You explained it like we'd understand it easily, you should next time try to think how much or how easily your target will understand the concept. It seemed to me that you didn't think about that. Next time, put that to mind. I'll congratulate you on your hard work though to make this.